You all do realize that sitting lower on the toilet is significantly healthier than sitting too high? Any doctor should be able to confirm that. The "original posture" for the big business is squatting, that's how evolution intended it, and anyone who has tried it, with the knees higher than the pelvis at that moment, will know what I mean.
But yes, every centimeter counts. I know it from my back...Well, unfortunately a few centimeters won't help you, better to sit more comfortably. And most of them are small shops.. But basically you are right, that's what stools are for...